recovery模式下支持ADB连接和串口操作
前言
Android平台下我们有时候会进入recovery下做一些操作,不管是通过ADB连接还是通过串口操作,都需要你的平台支持,不支持的话可以按照我们这篇文章进行修改。
正文
ADB连接
进入recovery后,我通过ADB连接会有如下报错
exec "/system/bin/sh": No such file or directory
1
根据提示,应该是需要把sh打包到recovery.img里面,不过这里要注意的是,recovery下执行的bin文件需要静态编译才行,所以我们需要修改sh编译的Android.bp文件:
diff --git a/external/mksh/Android.bp b/external/mksh/Android.bp
index 2bca561e9d..5fb3c67ad7 100644
--- a/external/mksh/Android.bp
+++ b/external/mksh/Android.bp
@@ -120,6 +120,7 @@ cc_defaults {
cc_binary {
name: "sh",
+ static_executable: true,
defaults: ["sh-defaults"],
}
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然后将编译出来的sh文件打包到recovery.img里面:
diff --git a/build/make/core/Makefile b/build/make/core/Makefile
index c58eb39839..027a32aee8 100644
--- a/build/make/core/Makefile
+++ b/build/make/core/Makefile
@@ -1398,6 +1398,8 @@ define build-recoveryimage-target
cp -rf $(item) $(TARGET_RECOVERY_ROOT_OUT)/$(newline))
$(hide) $(foreach item,$(recovery_fstab), \
cp -f $(item) $(TARGET_RECOVERY_ROOT_OUT)/etc/recovery.fstab)
+ $(hide) mkdir -p $(TARGET_RECOVERY_ROOT_OUT)/system/bin
+ $(hide) cp -r $(PRODUCT_OUT)/system/bin/sh $(TARGET_RECOVERY_ROOT_OUT)/system/bin
$(if $(strip $(recovery_wipe)), \
$(hide) cp -f $(recovery_wipe) $(TARGET_RECOVERY_ROOT_OUT)/etc/recovery.wipe)
$(hide) cp $(RECOVERY_INSTALL_OTA_KEYS) $(TARGET_RECOVERY_ROOT_OUT)/res/keys
@@ -1411,9 +1413,7 @@ define build-recoveryimage-target
$(hide) ln -sf prop.default $(TARGET_RECOVERY_ROOT_OUT)/default.prop
$(BOARD_RECOVERY_IMAGE_PREPARE)
$(if $(filter true,$(BOARD_BUILD_SYSTEM_ROOT_IMAGE)), \
- $(hide) mkdir -p $(TARGET_RECOVERY_ROOT_OUT)/system_root; \
- rm -rf $(TARGET_RECOVERY_ROOT_OUT)/system; \
- ln -sf /system_root/system $(TARGET_RECOVERY_ROOT_OUT)/system) # Mount the system_root_image to /system_root and symlink /system.
+ $(hide) mkdir -p $(TARGET_RECOVERY_ROOT_OUT)/system_root;)
$(hide) $(MKBOOTFS) -d $(TARGET_OUT) $(TARGET_RECOVERY_ROOT_OUT) | $(MINIGZIP) > $(recovery_ramdisk)
$(if $(filter true,$(PRODUCTS.$(INTERNAL_PRODUCT).PRODUCT_SUPPORTS_VBOOT)), \
$(hide) $(MKBOOTIMG) $(INTERNAL_RECOVERYIMAGE_ARGS) $(INTERNAL_MKBOOTIMG_VERSION_ARGS) $(BOARD_MKBOOTIMG_ARGS) --output $(1).unsigned, \
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以上操作后,就能正常ADB连接设备了。
串口操作
想要串口也能操作,也同样需要上面的步骤,除此之外还需要额外的修改,在进入recovery后需要拉起console服务:
diff --git a/device/emdoor/em_t6230_p4mme/init.recovery.mt8167.rc b/device/emdoor/em_t6230_p4mme/init.recovery.mt8167.rc
old mode 100644
new mode 100755
index f8ff23c8de..bb0087a70b
--- a/device/emdoor/em_t6230_p4mme/init.recovery.mt8167.rc
+++ b/device/emdoor/em_t6230_p4mme/init.recovery.mt8167.rc
@@ -14,12 +14,29 @@ on init
mkdir /config/usb_gadget/g1/configs/b.1 0777 shell shell
mkdir /config/usb_gadget/g1/configs/b.1/strings/0x409 0770 shell shell
mkdir /config/usb_gadget/g1/functions/ffs.adb
+
+on post-fs
+ # start console service earlier here
+ start console
+
+on property:ro.debuggable=1
+ start console
+
+service console /system/bin/sh
+ class core
+ console
+ disabled
+ user root
+ group shell log readproc
+ seclabel u:r:shell:s0
+ setenv HOSTNAME console
on property:ro.debuggable=0
# distinguish USB shoulde connect or not, i.e. CDP vs SDP
write /sys/class/udc/musb-hdrc/device/cmode 2
# set charging free due to it wait for USB activation
start adbd
+ start console
on property:sys.usb.ffs.ready=1
write /config/usb_gadget/g1/UDC "none"
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其它
虽然现在我们能ADB连接和串口操作了,但是常用的ls等命令却使用不了,因为recovery下system分区没有挂载,toybox和busybox等工具都没有,自然无法使用shell命令。这次我把toybox工具移植到recovery中,你也可以移植busybox和toolbox。
我们看external/toybox/Android.mk有专门编译给recovery使用的选项:
############################################
# static version to be installed in recovery
############################################
include $(CLEAR_VARS)
LOCAL_MODULE := toybox_static
LOCAL_SRC_FILES := $(common_SRC_FILES)
LOCAL_CFLAGS := $(common_CFLAGS)
LOCAL_STATIC_LIBRARIES := $(toybox_libraries)
# libc++_static is needed by static liblog
LOCAL_CXX_STL := libc++_static
LOCAL_MODULE_PATH := $(TARGET_RECOVERY_ROOT_OUT)/sbin
LOCAL_FORCE_STATIC_EXECUTABLE := true
LOCAL_POST_INSTALL_CMD := $(hide) $(foreach t,$(ALL_TOOLS),ln -sf ${LOCAL_MODULE} $(LOCAL_MODULE_PATH)/$(t);)
include $(BUILD_EXECUTABLE)
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只要把编译的模块名toybox_static加入到下面的文件就可以了:
diff --git a/system/core/shell_and_utilities/Android.bp b/system/core/shell_and_utilities/Android.bp
index 2e42b70993..ec53e59de6 100644
--- a/system/core/shell_and_utilities/Android.bp
+++ b/system/core/shell_and_utilities/Android.bp
@@ -17,5 +17,6 @@ phony {
"toolbox_vendor",
"toybox",
"toybox_vendor",
+ "toybox_static",
],
}
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结语
上面说了一大堆,其实最简单的方法只要在recovery启动的rc脚本中把system分区挂载一下就好了(逃~)。
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